Pneumatic weft guides for looms



June 30, 1964 v. svAT ETAL 3,139,118

PNEUMATIC WEFT GUIDES FOR Looms Filed May 19, 1958 4 Sheets-Sheet 1 June 30, 1964 v. svAnf ETAL 3,139,118

PNEUMATIC WEFT GUIDES FOR LOOMS Filed May 19, 1958 4 Sheehs-Sheerl 2 22 :20 21 @nnnjg June 30, 1964 v. SVA-n? ETAL PNEUMTIC WEFT GUIDES FOR LOOMS 4 Sheets-Sheet 3 Filed May 19, 1958 June 30, 1964 v. svATY ETAL PNEUMATIC WEFT GUIDES FOR LOOMS Filed May 19. 1958 4 Sheets-Sheet 4 N .bfi

United States Patent O 3,139,1ts PNEUMATIC WEET GUIDES FOR LOMS Vladimir Svaty, 4 U jean, Liberec IV, Czechoslovakia, and Ji Libnsky, 42S Brnenska, Liberec II, Czechoslovakia Filed May 19, 1958, Ser. No. 736,383 6 Claims. (Cl. 139-127) The present invention relates to a device for guiding the weft through the shed in weaving looms with a pneumatic picking mechanism.

Shuttleless weaving looms with a pneumatic picking mechanism, so-called jet looms, are known, in which the weft is inserted into the shed by means of an air stream produced by a suitably arranged nozzle. However, the weaving width of such looms is relatively small, being limited by the carrying capacity of the air stream entraining the weft. Due to mixing of the air of the jet with the surrounding air the power of the picking stream decreases, said stream being not capable to entrain the weft any further. Moreover, the weft, particularly its leading portion, does not fly smoothly or in a straight line, but forms loops; the leading end of the weft is thus deflected from the axis of the picking movement and the weft thread may easily be caught by the warp threads extending at right angles to the direction of iight of the weft. If the weft is caught in the warp threads, loops may easily be produced leading to faults in the fabric. These drawbacks are removed by arranging a suction tube at the other end of the shed, said suction tube having for its purpose to attract and straighten the flying weft. However, from the point of View of power consumption such a measure is uneconomical and renders the loom complex.

In some devices the shed is covered at the outside from both sides with plates in order to produce a channel facilitating the flight of the weft through the shed. Attempts have also been made to achieve a similar result with two troughs provided outside the shed, which, when approaching each other form a picking channel. The sides of both troughs are shaped in the manner of a gear toothing, the teeth of the upper trough engaging the gaps in the lower trough so as to effect a continuous closure of the sides of the channel. Into the lower portion of the teeth gaps warp threads are inserted at the same time so as to permit the opening of the warp. Both last mentioned methods have, however, the common drawback, that the warp threads remain at the upper and lower wall of the channel and may cause the leading end of the weft to get caught during the picking movement.

A device is further known in which the beat-up reeds are provided with two extensions approximately perpendicular to the plane of the reed which together with the plane of the reed form a trough guiding from three sides the air stream and having for its intended purpose to keep the flying weft out of contact with the warp threads.

A disadvantage of this arrangement is on the one hand its dependence on the reed, because when the density of warp threads is changed, the whole reed, the production of which is difficult, has to be changed, and on the other hand the shape of the trough from the aerodynamic point of View i.e. as far as the guiding of the air stream is concerned, is not perfect. The trough being open at one side, the air stream can expand at this side; this leads not only to a rapid reduction of the stream velocity, due to a diminishing ow of air, but also to a change of direction of the air stream, which becomes inclined under the influence of a component of the velocity of air escaping through the open wall of the trough.

All the above drawbacks are removed according to the invention by a so-called air condenser or comb comprising at teeth provided with incompletely closed apertures and engaging the shed during the picking opera- ICC tion, said apertures forming a channel which separates the weft from the warp threads.

The device according to the invention permits to increase the weaving width of shuttleless weaving looms with pneumatic picking mechanism/jet-looms/by the arrangement of a suitable picking channel for guiding the weft through the shed.

An example of the device according to the present invention is shown in the accompanying drawings, wherein FIG. l shows the overall arrangement of the device,

FIG. 2 a section of the picking comb,

FIG. 3 a side-view of a tooth,

FIG. 4 a sectional view along the line A-A of FIG. 3,

FIG. 5 a hollow tooth with means for the supply of a1r,

FIG. 6 a sectional View of the hollow tooth taken along the line B-B of FIG. 5, and

FIG. 7 is a section of the picking comb of FIG. 2, with details added.

A shaft 1 revolving with the revolutions of the weaving loom carries a crank disc 2 with a pin 3. Mounted on the pin 3 is a connecting rod 4, converting the circular motion of the crank pin 3 in an oscillatory reciprocal motion of swords 5 by the intermediary of pins 6. The swords 5 are mounted for rocking movement around a pivot 7. Secured by screws 8 to the sword 5 is a beam 9, in the groove 1t) of which a reed 11 is mounted with one of its ends and secured by means of a plate 12 and screws 13. Fixed by screws 14 to the beam 9 is a so-called condenser or comb 15 consisting of teeth 16 and spacers 17 (FIG. 2) inserted between the teeth and rigidly connected into one unit by means of two bolts 18.

The inlays 17, which are shorter than the teeth 16, alter regularly with the teeth so that gaps 19 forming a comb are produced in the upper part between the teeth. The teeth 16 are widened in their upper portion and provided with an aperture 20 (FIG. 3) with a slot 21. The aperture 20 which is in its greater part of circular shape blends with the slot 21 by a continuous transition portion 22. In the cross sectional View in FIG. 4 a conical recess 23 is apparent which forms a tapered cross section of the aperture in the direction 24. The tooth 16 is of chiefly flat formation and along its entire periphery, which engages the shed 26, i.e. where the gaps in the comb are located, the circumference of the teeth is sharpened to an edge 25.

FIGS. 5 and 6 show a hollow tooth made for example of thinwalled metal tubes by soldering. The tooth in the shown design consists of two attened tubes 29, 30 and an inlay 31 which are connected together e.g. by soldering in points 34, 35 so as -to form a unit corresponding in principle to the main functional dimensions of the aforesaid tooth 16, shown in FIG. 3. Air is supplied to the teeth through the tubes 33.

The device represented in FIG. l is shown on the one hand (with full lines) with the reed 11 in its rear extreme position and on the other hand (with dotted lines) with the reed in its forward extreme position at the moment of beat-up, when the whole condenser or comb 16 emerges from the warp, rocking below the plane 27 of the shed. A gap a is provided between the fabric and the upper contour of the air condenser or comb 16, said gap being suicient for the location of temples (not shown) and other auxiliary members.

A compressor 74 shown in FIG. 9 passes a compressed air through pipe 73 into a nozzle 71. The tip of the nozzle is located so as to direct a stream of air through the passage formed by the recesses 20 in the guiding teeth means 16. Spaced from the opening 71a through which the air stream passes into the passage there is a further opening '71b in the nozzle 71 through which the weft 72 is led into the nozzle and the air stream will carry the weft Ythrough the passage in selected sequence.

The apparatus described operates as follows:

At the moment when the slay is in its rear eXtreme position (shown in FIG. 1 in full lines), the weft is picked by means of a pneumatic apparatus (not shown) through an air nozzle of a known design by the influence of an air stream. The air nozzle has to be placedV on the loom so that the axis of the air stream projecting therefrom should, at the moment of picking, pass through the channel Ziifof Ithe condenser or comb 16. The air stream entraining the weft is then guided and directed by the channel in the condenser or comb and cannot expand freely to the sides, its kinetic energy being thus maintained and utilized to a greater distance than with a free current in the atmosphere. i

The directing influence on the air stream of the condenser is assisted by the conical transition portion 23 or recess which forms an inlet to the various apertures of the teeth (FIG. 4). As long as the velocity of air liowing through the channel is sufficiently high, the air does not penetrate through the gaps 19 between the teeth out of the channel, but on the contrary air is sucked in from the l shed in downward direction under simultaneous closingV of the shed. As soon as the weft, lying in the channel, meets the warp threads during this movement, it slides out of the picking channel through the slot 21 during further movement. The reed 11 then beats up the weft to the fabric 2S in a normal way. Upon return movement of the slay the condenser or comb 16 enters the shed again through the lower half of the warp and, after reaching the rear extreme positionV the described process is repeated.v

Towards the end part of the channel the velocity of the air streaming through the channel drops due to the resistance of the teeth. When the condenser is of a substantial length, such as required for weaving goods of considerable width, it may happen that the velocity of the air would be insuflicient for reliably entraining the leading end of the weft. This deficiency may be removed by inserting hollow teeth 16a designed e.g. in a way shown in FIGS. 5 and 6 and having for their purpose to receive air through the open ends of conduits in the direction of arrows 33 and supply the additional air through suitably Vlocated discharge apertures 32 into the space of the pickin this way it is theoretically possible to carry out a picking channel of any desired length with a satisfactory operation.

When applying such teeth with a supply of additional air, a channel has to be used, which is closed as far as possible along its entire circumferenece. If, for instance, such teeth were used in connection with trough shaped channels, they would lose their effect and, on the contrary,V assist in deflecting the weft from the axis of the channel to the outside. v

`For dense warps a condenser or comb carrying out a longitudinal lmovement in thedirection of the weft is used with preference. During the time when the condenser is outside the Warp, it is shifted in longitudinal direction through a small distance so that the warp threads, lying between the teeth, may be changed when the next submersion into the warp takes place. The formation oflongitudinal strips in the fabric is thus prevented, which otherwise would be caused by the warp threads being pushed apart always in the same place by the teeth of the condenser.

It is an advantage of the arrangement according to the invention over a direct pneumatic picking through the shed, that the possibility of the weft being caught by the warp threads when flying through the shed is prevented, because the walls of the channel of theV air condenser, which may be carried out of various materials, of metal or of synthetic material, are far smoother than the surface formed by the warp threads in the shed and elimi- -nate therefore any possibility of the weft becoming caught.

A further advantage is a lower consumption of air and therefore also of driving power, because due to the air stream being giuded through the condenser channel, an expansion of the stream is avoided, such expansion involving also a drop of its efficiency in guiding the weft. The guiding of the weft is therefore more reliable, it being also possible to achieve with the same consumption of air greater weaving Vwidths than with the pneumatic picking by a free air stream. The air condenser shields also the air stream, entraining the weft, from outer infiuences, because irregular currents and whirls occur in the Vicinity of the picking path of the weft, upon movement of the reed and other devices, said currents and whirls having a disturbing eifect on the smooth flight of the weft.

We claim:

1. in a pneumatic loom, in combination, a row of guiding members, each of said guiding members including a thin iiat air guiding portion forming an opening having a narrow outlet gap, said openings being aligned to form an air-guiding passage, and said gaps being aligned to form a narrow slot; nozzle means for blowing a stream of air entraining a weft into said passage; and rockable slay means supporting said guide members for movement therewith between an air-guiding position in which said guide members are adapted to be located between warp threads, and said passage is adapted to be located in a warp shed aligned with said nozzle means for receiving and guiding a stream of air entraining a weft thread so that dissipation of the stream is prevented, and a retracted position adapted to be spaced from the plane of the warp threads to permit the warp threads to assume-closely adjacent positions whereby a weft thread in said passage is held by the warp threads to pass through said narrow slot during movement of said guiding members to said retracted position.

2. In a pneumatic loom, in combination, a row of guiding members, each of said guiding members including a thin iiat air guiding portion forming an opening having a narrow outlet gap, said openings being aligned to form an air-guiding passage, and said gaps being aligned to from a narrow slot, each air Vguiding portion having a sharp outer edge; nozzle means for blowing a stream of air entraining a weft into said passage; and slay rockable means supporting said guide members for movement therewith between an airfguiding position in which said guide members are adapted to be located between warp threads, and said passage is adapted to be located in a warp shed aligned with said nozzle means for receiving and guiding a stream of air entraining a weft thread so that dissipation of the stream is prevented, and a retracted position adapted to'be spaced from the plane of the warp threads to permit the warp threads to assume closely adjacent positions whereby a weft thread Vin said passage is held by the warp threads to pass through said narrow slot during movement Vof said guiding members to said retracted position, said sharp edges of said guid- L? ing portions being adapted to separate the warp threads during movement of said guiding members from said retracted position to said air-guiding position.

3. In a pneumatic loom, in combination, a row of guiding members, each of said guiding members including a thin flat air guiding portion forming an opening having a narrow outlet gap, said openings being aligned to form an air-guiding passage, and said gaps being aligned to form a narrow outlet slot; nozzle means for blowing a stream of air entraining a wett into said passage; and rockable slay means supporting said guide members for movement therewith between an air-guiding position in which said guide members are adapted to be located between warp threads, and said passage is adapted to be located in a warp shed aligned with said nozzle means for receiving and guiding a stream of air entraining a weft thread so that dissipation of the stream is prevented, and a retracted position adapted to be spaced from the plane of the warp threads to permit the warp threads to assume closely adjacent positions, said slot extending substantially in the plane of the Warp threads in said air guiding position and substantially parallel to the plane of the warp threads in said retracted position whereby a weft thread in said passage is held by the warp threads to pass through said narrow slot during movement of said guiding members to said retracted position.

4. In a pneumatic loom, in combination, a row of guiding members, each of said guiding members including a thin flat air giuding portion forming an opening having a narrow outlet gap, each opening having a wider portion on one side of the respective guiding portion and having a reduced portion tapering toward the other side of said guiding portion, said openings being aligned to form an air-guiding passage, and said gaps being aligned to form a narrow slot; nozzle means for blowing a stream of air entraining a weft into said passage; and rockable slay means supporting said guide members for movement therewith between an air-guiding position in which said guide members are adapted to be located between warp threads, and said passage is adapted to be located in a warp shed aligned with said nozzle means for receiving and guiding a stream of air entraining a weft thread while said reduced portion of each opening guides the stream of air toward the central part of the wider portion of the next adjacent opening so that dissipation of the stream is prevented, and a retracted position adapted to be spaced from the plane of the warp threads to permit the Warp threads to assume closely adjacent positions whereby a weft thread in said passage is held by the warp threads to pass through said narrow slot during movement of said guiding members to said retracted position.

5. In a pneumatic loom, in combination, a row of guiding members, each of said guiding members including a thin iiat air guiding portion forming an opening having a narrow outlet gap, said opening being aligned to form an air-guiding passage, and said gaps being aligned to form a narrow slot, at least one of said guide members being formed with a conduit terminating in a plurality of discharge apertures in said air-guiding portion and disposed about said opening so that compressed air supplied to said conduit flows out of said discharge apertures substantially in direction of said air guiding passage; nozzle means for blowing a stream of air entraining a weft into said passage; and rockable slay means supporting said guide member for movement therewith between an air-guiding position in which said guide members are adapted to be located between warp threads, and said passage is adapted to be located in a warp shed aligned with said nozzle means for receiving and guiding a stream of air entraining a weit thread so that dissipation ot the stream is prevented, and a retracted position adapted to be spaced from the plane of the warp threads to permit the warp threads to assume closely adjacent positions whereby a weft thread in said passage is held by the warp threads to pass through said narrow slot during movement of said guiding members to Said retracted position.

6. In a pneumatic loom, in combination, a row of guiding members, each of said guiding members including a thin flat air guiding portion forming an opening having a narrow outlet gap, each opening having a wider portion on one side of the respective guiding portion and having a reduced portion tapering toward the other side oi said guiding portion, said openings being aligned to form an air-guiding passage, and said gaps being aligned to form a narrow slot, each air guiding portion having a sharp outer edge; nozzle means for blowing a stream of air entrainirig a weft into said passage; and rockable slay means supporting said guide members for movement therewith between an air-guiding position in which said guide members are adapted to be located in a warp shed aligned with said nozzle means for receiving and guiding a stream of air entraining a weft thread while said reduced portion of each opening guides the stream of air into the wider portion of the next adjacent opening so that dissipation of the stream is prevented, and a retracted position adapted to be spaced from the plane of the warp threads to permit the warp threads to assume closely adjacent positions, said slot extending substantially in the plane of the warp threads in said air guiding position and substantially parallel to the plane of the warp threads in said retracted position whereby a weft thread in said passage is held by the warp threads to pass through said narrow slot during movement of said guiding members to said retracted position, said sharp edges of said guiding portions being adapted to separate the warp threads during movement of said guiding members from said retracted position to said air-guiding position.

References Cited in the file of this patent UNITED STATES PATENTS 1,721,940 Ballou July 23, 1929 2,316,703 Moessinger Apr. 13, 1943 2,538,630 Rusnov Ian. 16, 1951 FOREIGN PATENTS 366,473 Italy Dec. 28, 1938 

1. IN A PNEUMATIC LOOM, IN COMBINATION, A ROW OF GUIDING MEMBERS, EACH OF SAID GUIDING MEMBERS INCLUDING A THIN FLAT AIR GUIDING PORTION FORMING AN OPENING HAVING A NARROW OUTLET GAP, SAID OPENINGS BEING ALIGNED TO FORM AN AIR-GUIDING PASSAGE, AND SAID GAPS BEING ALIGNED TO FORM A NARROW SLOT; NOZZLE MEANS FOR BLOWING A STREAM OF AIR ENTRAINING A WEFT INTO SAID PASSAGE; AND ROCKABLE SLAY MEANS SUPPORTING SAID GUIDE MEMBERS FOR MOVEMENT THEREWITH BETWEEN AN AIR-GUIDING POSITION IN WHICH SAID GUIDE MEMBERS ARE ADAPTED TO BE LOCATED BETWEEN WARP THREADS, AND SAID PASSAGE IS ADAPTED TO BE LOCATED IN A WARP SHED ALIGNED WITH SAID NOZZLE MEANS FOR RECEIVING AND GUIDING A STREAM OF AIR ENTRAINING A WEFT THREAD SO THAT DISSIPATION OF THE STREAM IS PREVENTED, AND A RETRACTED POSITION ADAPTED TO BE SPACED FROM THE PLANE OF THE WARP THREADS TO PERMIT THE WARP THREADS TO ASSUME CLOSELY ADJACENT POSITIONS WHEREBY A WEFT THREAD IN SAID PASSAGE IS HELD BY THE WARP THREADS TO PASS THROUGH SAID NARROW SLOT DURING MOVEMENT OF SAID GUIDING MEMBERS TO SAID RETRACTED POSITION. 